The present invention pertains to new compositions of matter, particularly aryl trifluoromethoxytetrafluorosulfuranes, which may be derivatized to yield highly electrically polar molecules, particularly novel liquid crystal compositions having high dielectric anisotropies.
Liquid crystals are an essential component of many types of optical displays. The usefulness of liquid crystals for application in this area is related to the strength and position of the polar groups in the liquid crystal molecule and the degree of dielectric anisotropy the liquid crystal exhibits (1). Accordingly, the literature shows that a number of liquid crystals used in active matrix displays have evolved into those containing highly polar head groups (1,2), quite notably perfluorinated ones such as CF3, which impart a dipole on the molecule in order to achieve an improved dielectric anisotropy and hence enhanced performance.
Early research showed that the introduction of additional lateral fluorine atoms would augment the molecular dipole moment, and therefore increase the dielectric anisotropy and enhance performance. However, this process of lateral fluorination had a negative effect on other properties of the product, such as clearing points of the liquid crystals. Therefore, research began to focus on identification of new, highly polar terminal groups, which induce reasonably high clearing points while still increasing the dielectric anisotropy (2).
The search for new liquid crystal head groups is ongoing, as evident from the application of the highly polar —SF5 group in the synthesis of nematic liquid crystals (3,4). While an evaluation of physical properties demonstrated that —SF5-based liquid crystals were a polar class of liquid crystals compatible with active matrix display technology, several less favorable properties also became evident. First, the experimentally determined dielectric anisotropies of the newly synthesized —SF5 derivatives were far lower that predicted. Additionally, the liquid crystals had a relatively high rotational viscosity, as well as a relatively high melting point (3).
The chemical moiety, —SF4—OCF3, has been reported in the literature as a component of a handful of inorganic compositions including those best characterized such as F5SOCF3 (5) and the cis- and trans- isomers of F4S(OCF3)2 (6). A recent patent (7) suggests liquid crystal compositions containing the —CF2—SF4—OCF3 group linked to various organic structures; however, no such compositions were synthesized or explicitly described (see also (7a)). In particular, there is no prior art or actual compound where the SF4—OCF3 group is attached to an organic moiety. Although reactions between aryl sulfides and F3COF (fluoroxytrifluoromethane) have been reported (8), the investigators did not disclose any products containing S—O—CF3 bonded centers. Otherwise, the use of —SF4—OCF3 as a functional group has remained unexplored.
Accordingly, it is desired to provide liquid crystal compositions having high dielectric anisotropies, which do not substantially suffer from the aforementioned deficiencies of other liquid crystal compositions.
All references cited herein are incorporated herein by reference in their entireties.